1705 as abbreviation of reputation (n.); upon rep "I swear it" was a common 18c. slang asseveration. As a shortening of repetition (n.) it is recorded from 1864, originally school slang; as a shortening of representative (n.), especially "sales representative," it is attested from 1896. As an abbreviation of repertory (company) it is recorded from 1925.

rep 3

rep 4

The Dictionary of American Slang, Fourth Edition by Barbara Ann Kipfer, PhD. and Robert L. Chapman, Ph.D.Copyright (C) 2007 by HarperCollins Publishers.Cite This Source

rep in Technology

programming A directive used in IBMobject code card decks (and later PTF Tapes) to REPlace fragments of already assembled or compiled object code prior to link edit. Recompiling or reassembling the source code to produce a whole new object module was only possible if the source code was available, which it rarely was (if you had the object you were lucky!) It was also quicker to apply incremental changes with REP cards and they also circumvented the checksums and card sequence numbers present in the object code. (1998-07-16)